Limited broadcasts MUST NOT be forwarded. Limited broadcasts MUST NOT be discarded. Limited broadcasts MAY be sent and SHOULD be sent instead of directed broadcasts where limited broadcasts will suffice.
Some routers contain UDP servers which function by resending the requests (as unicasts or directed broadcasts) to other servers. This requirement should not be interpreted as prohibiting such servers. Note, however, that such servers can easily cause packet looping if misconfigured. Thus, providers of such servers would probably be well advised to document their setup carefully and to consider carefully the TTL on packets that are sent.